Several years back, I used sugar bottles during a skit in Grand Cayman for their Pirates Week Tryal Of The Pirates. The problem I had wasn't the humidity and the bottles getting sticky, the problem was having one left for the skit. Broke 2 flying down there, i fell off a table and the last one was the one they used to hit me in the head. During the skit, it sat on the drunk defense attorneys table. Every time he moved, the bottle weaved like it was going to fall. I was having kitten back stage during this as it was the last one. The alternative they came up with was a lightly glued glass Coke bottle!!!!! If that had been used I would have either been in the hospital there or shipped back in a pine box!!! I really don't think that the humidity that time of the year will be an issue. We were in Cayman in late october and down there it kept raining and the humidity was at least 80 - 90%.
Animal